Web sources

Apply for unemployment benefits, Dept. of Unemployment Assistance
You should apply for unemployment benefits during your first week of total or partial unemployment. Most claims are processed within 21-28 days after filing. It may take longer if there is an issue with your claim.

Board of Review decisions, Board of Review
The Board decides unemployment appeals from hearings conducted by the Department of Unemployment Assistance. Site provides selected opinions only. "The Board of Review decisions available on this website have been selected for posting because, in the Board’s opinion, they contain significant issues, create new precedent, or may provide useful guidance to parties and their representatives."

Has the DUA asked you to return money they paid you?, MassLegalHelp, 2013.
If the DUA says that you were overpaid, you can challenge DUA's decision, or the amount of the overpayment. Even if you agree that you were overpaid, you may not have to pay it back if you meet certain conditions.

How do you appeal to the court?, Mass. Legal Services.
Explains how to appeal a final decision of the Board of Review. Appendix M includes a sample complaint for judicial review.

Unemployment insurance (UI) online, Mass. Dept. of Unemployment Assistance
Claimants, employers, and third party administrators (TPAs) can log in to their UI Online accounts to file claims, access the Claimant Inbox, report wages, view correspondence, and more. UI Online is available daily from 6 a.m. to 10 p.m.

Your rights in the workplace , Nolo, 2018.
Chapter 11: Unemployment "provides information about unemployment insurance or unemployment compensation such as some specific state nuances on unemployment insurance programs run jointly by the federal government and the states. It also discusses disqualifying behavior and filing a claim." Requires free library card for access.